Knee hight adjustment screw tightness issue

ZombiWelder

Registered
Registered
Joined
Mar 5, 2018
Messages
47
Gentlemen!
Kind of embarrassed to ask , must be something dumb and simple but I'm having issues with the acme screw on my mills knee. At some point it got a bit tight in some spots I assumed just chips got into threads. Some time after I went to clean the entire mill and after i cleaned everything the knee seemed to have gotten even tighter, about couple inches above the bottom of the travel . I thought must be some notorious chip that's below the nut at the base of the mill , so I strapped the knee to the head , and loosened the cone shaped lets call it "nut housing " and ran it up and down without any significant issues. Then I bolted it back down and knee got way tight. I'm assuming it's gotta have just the right alignment but my efforts to tap that nut housing into its happy place failed. It was late in the day so I figured I'll take a break, maybe ask some advice before I get back at her. Is there some clever trick to realign things? Am i 20181109_191549.jpgmissing something?
Thanks a zillion!
 
just spit balling here, the main column hasn't shifted on the base causing the misalignment has it?

Hmm,
Something too look at, thank you ! The mill is smothered in bondo, so would not be hard to see.
 
I would think the Bondo may be your friend if it shows a crack where there was movement. Also another thought knee gibs in good order?
 
I would think the Bondo may be your friend if it shows a crack where there was movement. Also another thought knee gibs in good order?

It only one gib, I guess it won't hurt to check but turning the handle it felt like a binding screw
 
I get what you are saying, hard to fix or help fix things when you cant touch or feel. I was hoping someone else would hop in here with a fix or idea also being I think 6x26 machines like yours are fairly popular
 
You do need to keep the knee sliding surfaces well lubricated !

However since you have run the nut up and down the screw, and its free, the binding can only be somewhere in the hight control mechanism. Since column alignment has been mentioned I assume that you have already checked that.

I'm guessing lack of lubrication or possibly a failing bearing in the gear at the top.
 
I would pull the gib and do some house cleaning on the ways, then reinstall gib with copious amounts of oil on ways and gib.
There is a positioner bolt on both ends of the gib to keep it tensioned properly(close to snug but with a little play). If the gib
slips deeper because the bolts are not tensioned correctly, the knee will surely bind.
 
Back
Top